X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Fcopy_file.c;h=d804eccfaee8009cf55f6957233f6685b9f1e1f9;hb=defc1ea34074e7882724c460260d307cdf981a70;hp=86449f27c853b0b654939a07d0243479e4ce1db6;hpb=fa05074eeed1a6a25393d4b466c7512112f39104;p=oweals%2Fbusybox.git

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index 86449f27c..d804eccfa 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -29,6 +29,7 @@
 // for POSIX mode to give reasonable error message
 static int ask_and_unlink(const char *dest, int flags)
 {
+	int e = errno;
 #if DO_POSIX_CP
 	if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
 		// Either it exists, or the *path* doesnt exist
@@ -50,7 +51,16 @@ static int ask_and_unlink(const char *dest, int flags)
 			return 0; // not allowed to overwrite
 	}
 	if (unlink(dest) < 0) {
-		bb_perror_msg("cannot remove '%s'", dest);
+#if ENABLE_FEATURE_VERBOSE_CP_MESSAGE
+		if (e == errno && e == ENOENT) {
+			/* e == ENOTDIR is similar: path has non-dir component,
+			 * but in this case we don't even reach copy_file() */
+			bb_error_msg("cannot create '%s': Path does not exist", dest);
+			return -1; // error
+		}
+#endif
+		errno = e;
+		bb_perror_msg("cannot create '%s'", dest);
 		return -1; // error
 	}
 	return 1; // ok (to try again)
@@ -61,7 +71,7 @@ static int ask_and_unlink(const char *dest, int flags)
  *  0 copy is made or user answered "no" in interactive mode
  *    (failures to preserve mode/owner/times are not reported in exit code)
  */
-int copy_file(const char *source, const char *dest, int flags)
+int FAST_FUNC copy_file(const char *source, const char *dest, int flags)
 {
 	/* This is a recursive function, try to minimize stack usage */
 	/* NB: each struct stat is ~100 bytes */
@@ -71,6 +81,7 @@ int copy_file(const char *source, const char *dest, int flags)
 	signed char dest_exists = 0;
 	signed char ovr;
 
+/* Inverse of cp -d ("cp without -d") */
 #define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)
 
 	if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
@@ -141,6 +152,8 @@ int copy_file(const char *source, const char *dest, int flags)
 				bb_error_msg("target '%s' is not a directory", dest);
 				return -1;
 			}
+			/* race here: user can substitute a symlink between
+			 * this check and actual creation of files inside dest */
 		} else {
 			mode_t mode;
 			saved_umask = umask(0);
@@ -217,12 +230,22 @@ int copy_file(const char *source, const char *dest, int flags)
 		return 0;
 	}
 
-	if (S_ISREG(source_stat.st_mode)
-	 /* DEREF uses stat, which never returns S_ISLNK() == true. */
+	if (/* "cp thing1 thing2" without -R: just open and read() from thing1 */
+	    !(flags & FILEUTILS_RECUR)
+	    /* "cp [-opts] regular_file thing2" */
+	 || S_ISREG(source_stat.st_mode)
+	 /* DEREF uses stat, which never returns S_ISLNK() == true.
+	  * So the below is never true: */
 	 /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
 	) {
 		int src_fd;
 		int dst_fd;
+		mode_t new_mode;
+
+		if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) {
+			/* "cp -d symlink dst": create a link */
+			goto dont_cat;
+		}
 
 		if (ENABLE_FEATURE_PRESERVE_HARDLINKS && !FLAGS_DEREF) {
 			const char *link_target;
@@ -246,18 +269,24 @@ int copy_file(const char *source, const char *dest, int flags)
 		if (src_fd < 0)
 			return -1;
 
+		/* Do not try to open with weird mode fields */
+		new_mode = source_stat.st_mode;
+		if (!S_ISREG(source_stat.st_mode))
+			new_mode = 0666;
+
 		/* POSIX way is a security problem versus symlink attacks,
-		 * we do it only for dest's which are device nodes,
-		 * and only for non-recursive, non-interactive cp. NB: it is still racy
-		 * for "cp file /home/bad_user/device_node" case
-		 * (user can rm device_node and create link to /etc/passwd) */
+		 * we do it only for non-symlinks, and only for non-recursive,
+		 * non-interactive cp. NB: it is still racy
+		 * for "cp file /home/bad_user/file" case
+		 * (user can rm file and create a link to /etc/passwd) */
 		if (DO_POSIX_CP
-		 || (dest_exists && !(flags & (FILEUTILS_RECUR|FILEUTILS_INTERACTIVE))
-		     && (S_ISBLK(dest_stat.st_mode) || S_ISCHR(dest_stat.st_mode)))
+		 || (dest_exists
+		     && !(flags & (FILEUTILS_RECUR|FILEUTILS_INTERACTIVE))
+		     && !S_ISLNK(dest_stat.st_mode))
 		) {
-			dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode);
 		} else  /* safe way: */
-			dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode);
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
 		if (dst_fd == -1) {
 			ovr = ask_and_unlink(dest, flags);
 			if (ovr <= 0) {
@@ -265,7 +294,7 @@ int copy_file(const char *source, const char *dest, int flags)
 				return ovr;
 			}
 			/* It shouldn't exist. If it exists, do not open (symlink attack?) */
-			dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode);
+			dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
 			if (dst_fd < 0) {
 				close(src_fd);
 				return -1;
@@ -273,8 +302,7 @@ int copy_file(const char *source, const char *dest, int flags)
 		}
 
 #if ENABLE_SELINUX
-		if (((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT)
-		    || (flags & FILEUTILS_SET_SECURITY_CONTEXT))
+		if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT))
 		 && is_selinux_enabled() > 0
 		) {
 			security_context_t con;
@@ -301,8 +329,13 @@ int copy_file(const char *source, const char *dest, int flags)
 		}
 		/* ...but read size is already checked by bb_copyfd_eof */
 		close(src_fd);
+		/* "cp /dev/something new_file" should not
+		 * copy mode of /dev/something */
+		if (!S_ISREG(source_stat.st_mode))
+			return retval;
 		goto preserve_mode_ugid_time;
 	}
+ dont_cat:
 
 	/* Source is a symlink or a special file */
 	/* We are lazy here, a bit lax with races... */